Bluegrass and Jazz, Meeting in More Than the Middle

Chris Thile and Brad Mehldau come from different worlds but the same species, and whatever feels unlikely about their pairing is eclipsed by what feels perfectly natural. Mr. Thile, the mandolinist and singer with Punch Brothers, is a progressive-bluegrass pacesetter; Mr. Mehldau is the most influential jazz pianist of the last 20 years. Both are team players who can still give the impression of aesthetic self-containment. Both love Bach and the Beatles, and both have developed fan bases bigger and broader (and younger) than their genre silos can accommodate.

On Tuesday night they played a sold-out show at the Bowery Ballroom, kicking off a nine-city tour that ends in Austin, Tex., on April 20. They worked together as an acoustic duo with no reinforcements, Mr. Thile cradling his mandolin in the crook of an arm and Mr. Mehldau seated at a Steinway that stretched nearly the length of the stage. There was some courteous give and take in their 90-minute show, but more often a balance of enthusiastic risk and intuitive accord. It felt unhurried but went by quickly.